I've made two of my own using an old dorm fridge, 25 feet of copper tubing, a five gallon bucket, and a water trap... junk I already had laying around. Works great. Just having a bunch of tubing after the tank won't cool the air enough for moisture in the lines to condense when it's hot and humid outside.
You are not using the full cfm of your compressor when spraying. You just need to handle to cfm of your spray guns. Trust me, it works great and a lot of folks on here use them. I only turn mine on when spraying or using my blast cabinet.The harbor freight dryer will not handle the cfm rating of my compressor.